Research On Characteristics And Influence Factors Of Soil Infiltration In Three Gorges Of Yangtze River

Three Gorges Reservoir area is located in the upper reaches of the Yangtze River. The difference of natural geographical elements is very significant. It’s an important biodiversity Nature Reserve in China. Due to the internal natural elements are complex and diverse, the Yangtze River Three Gorges section becomes the natural disaster stricken area. The object of this paper is the forest soil of different heights in the Three Gorges Reservoir area of the Yangtze river, based on the natural and human basic situation of the experimental area. Through field tension infiltration experiment and indoor ring knife infiltration experiment, analysis of infiltration characteristics of different types of soil and vertical layered soil. At the same time, the infiltration characteristics of forest soil and tea garden soil are compared. It seems that in the promotion of soil water infiltration, runoff generation and less important to maintain soil and other aspects of the forest soil. Research shows:(1)Dalaoling native forest soil average infiltration rate is 11.24mm/min. Baishuitou secondary forest soil infiltration rate is 9.63mm/min. Native forest soil infiltration rate is higher than the secondary forest soil. The elevation of primary forest is higher, and the vegetation quantity is more abundant. So the soil porosity is higher, and the infiltration rate is higher. Secondary forests are greatly influenced by the impact of human activities, vegetation dominated by oak forest, secondary forest and plantation of sparse and low development degree of soil, so infiltration rate is low.(2)The infiltration rate of different layers in the reservoir area is different. It shows: Humus layer> Leaching deposition> Parent material. With the deepening of soil depth, soil bulk density, soil texture and soil organic matter are changed, the infiltration rate of the soil showed a decreasing trend from the surface to the surface.(3)The average infiltration rate of forest sample plots and tea plantation soil was 10.44mm/min and 0.7mm/min, respectively, The infiltration rate of forest soil is much higher than that of tea garden soil. In the sample plots, the tea plantation is the most affected soil type affected by human activities, On the one hand, the physical and chemical properties of the soil is changed, and the porosity becomes smaller, so the infiltration rate is reduced; On the other hand, the transformation of tea garden soil is low, and in the course of cultivation, the soil erosion is serious, so the infiltration rate is reduced.(4)According to the SPSS software on permeability factors affect the reservoir area soil infiltration for correlation analysis, the correlation coefficient of soil organic matter and root are in the range between 0.83-0.96 and 0.83-0.97, and soil water rate was very significant positive correlation; four plots of soil volumetric weight correlation coefficients were -0.96,-0.95,0.86 and 0.89, and soil water infiltration rate was very significant negative correlation.